If your drives have a fault signal you can feed that to Mach to do an E-Stop.
The way I do it is via my PLC, heres a screenshot of the E-Stop to Mach via my PLC but you could do similar with a Brain. I also have the enables to the drives in a similar fashion in the PLC so if a limit or E-Stop button or drive faults then enables are taken away from the drives.
Hood